Sanguinarine canadensis is known as Bloodroot, Puccoon, Tetterwort, etc. and is an herb native to North America. The plant and its juices have been used for various purposes during pre-history as well as written history. It has been used as a natural historic folk remedy medicine. The plant has been generally used whole either undried (fresh) or dried. The usual procedure is to powder the dried plant and mix it with a carrier. This folk remedy has been tried for such things as asthma, bronchitis, dysentery, ringworm, and a substantial list of other ailments.
Sanguinarine, chelerythrine, and other benzophenanthridine alkaloids are known alkaloids defined as isoquinolines. Plant sources for these alkaloids fall into various species; the Papaveraceae, Fumariaceae, and Rutaceae families. Recoveries of these alkaloids from Sanguinaria Canadensis L. and Macleaya species are described in U.S. Pat. Nos. 4,145,412; 4,406,881; 4,517,172; 4,590,061; 4,599,228; 4,683,133; 4,689,216; 4,767,861; and 4,769,452. Production of these alkaloids from plant tissue culture has been described in Plant Cell Reports (1988) 7:410-413.
Purification of the Benzophenanthridine alkaloids into individual alkaloids without using known chromatographic methods is also described in the foregoing U.S. patents.
The use of an extract containing these benzophenanthridine alkaloids from Sanguinaria Canadensis as an ingredient in an oral cleansing preparation is also disclosed in the foregoing U.S. patents.
Other uses for the extract of Sanguinaria Canadensis L. are reported as a plaque disclosing agent in U.S. Pat. Nos. 4,517,172 and 4,590,061.
It is known that mouthrinses and dentifrices containing sanguinaria extract are effective anti-plaque and anti-gingivitis agents. They are also effective against oral malodor and calculus. Early patents, U.S. Pat. Nos. 209,331 and 2,344,830 describe the use of sanguinaria in combination with zinc chloride. Although there is no indication that zinc chloride is needed to maintain efficacy, sanguinaria extract is typically used in combination with zinc chloride or other metallic salts, such as stannous chloride, in dentifrices, as in U.S. Pat. No. 4,689,216. When sanguinaria extract is combined with zinc chloride in a mouthrinse vehicle the pH is usually adjusted to 3. Prior art teaches that zinc mouthrinses are adjusted to pH 3 to prevent the formation of insoluble zinc compounds such as zinc hydroxide and zinc oxychloride. See U.S. Pat. No. 4,289,755. In addition, solutions of sanguinaria are acidified to prevent the formation of pseudo base forms of the benzophenanthridine alkaloids present in the extract. Pseudo base forms of the alkaloids present in the extract begin to form at approximately pH 5.6 (Jones, et al. J. of Natural Products, Vol 49, No. 6, pp. 1109-1111, November-December 1986).
In addition, the extract was adjusted to a pH of 3 to maintain chemical stability of the extract and prevent the formation of brownish to black precipitates which are assumed to be due to the condensation of tannins and to the presence of lignin-like material in the extract. It has been found that 1% solutions of sanguinaria extract filtered at pH's of 3, 4, and 5 will form additional precipitates on standing with the minimum amount of precipitate forming at pH 3. This indicates that at pH's above 3 undesirable condensation and/or polymerization begins to occur.
The alkaloid extract when made into an oral rinse, dentifrice, or oral care product is an excellent breath freshener, and also an anti-plaque and anti-gingivitis agent. When combined with zinc chloride, however, the pH of the rinse needs to be acidic (pH=3) for a number of reasons. Zinc containing rinses are generally formulated at a pH of 3 for stability purposes as set forth in U.S. Pat. No. 4,289,755. Other patent art teaches that higher pH's are attainable through the use of glycine. See U.S. Pat. No. 4,339,432. Rinses at low pH's, especially with zinc chloride, also taste acrid.